Hydraulic System Design for Manual Press Brake

As the title states I'm trying to figure out the simplest/most cost effective way to setup a press so that it will have adjustable limit switches for the press stroke and retract stroke while also having a manual valve to move the ram when not using the limit switches. A latching start/stop pendant or button is my original thought but I'm not sure how to implement it with the plumbing. If someone could help me out with a sketch or point me to a diagram already drawn that would be great.

Scrap your idea of building a press brake and come get my 3/16" x 10' apron brake, LOL...

Portable Welder said:

Scrap your idea of building a press brake and come get my 3/16" x 10' apron brake, LOL...

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If it was free and you covered half the shipping I'd probably take ya up on it lol. Don't think that will do what I want to do unfortunately

So what your wanting is a solenoid valve, and then for "Feel"
you want a separate hand valve ?

I'm thinking you could just plumb them in parallel.

Limit switches wired to a plc, manual actuator wired to it as well. Maybe a selector switch wired in to select between manual vs automatic.

With the price of a bunch of redundant hydraulic components eliminated a cheap plc from automation direct would be covered with ease.

Mebfab said:

Limit switches wired to a plc, manual actuator wired to it as well. Maybe a selector switch wired in to select between manual vs automatic.

With the price of a bunch of redundant hydraulic components eliminated a cheap plc from automation direct would be covered with ease.

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"Manual Actuator" meaning some form of switch ?

yes. Although no "feel".

Next question, one or more cylinders? If more then one how to balance? Or plan to bottom out? And do you want a press, or a press brake?

If building your own, how about copying what iroqious does?

digger doug said:

So what your wanting is a solenoid valve, and then for "Feel"
you want a separate hand valve ?

I'm thinking you could just plumb them in parallel.

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Hand valve(just like a log splitter would use) so you could set where the bottom limit switch should be.

Mebfab said:

yes. Although no "feel".

Next question, one or more cylinders? If more then one how to balance? Or plan to bottom out? And do you want a press, or a press brake?

If building your own, how about copying what iroqious does?

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One cylinder press brake just like iroqious does(levers). I just looked at automation's CLICK PLC. That looks interesting. I have a good buddy that is a PLC guru so he could help me out for sure. Sequence of operation would be some sort of manual way to move the ram where it's needed, set limit switches, hit go button, goes down to hit limit, then returns to other limit and waits for cycle to repeat. Don't have a clue how the hydraulic schematic would look on this.

Instead of the endswitch I would use a DRO with a potentional free switch that is programmable
Most DRO`s for EDM have this feature

Peter

The hyd schematic would look the same as any other valve running a double acting cylinder (assuming single cylinder variant), except that the valve would need to be an electrically operated proportional valve that the PLC controls. Will need some kind of amplifier between plc and valve too. If going that far than put a linear encoder on the ram and have the PLC watch that too and be able to set the lower limit and upper return point via touchscreen or some other means directly tot he PLC, that way it can be more precise and actually slow the cylinder speed down when getting near the desired position. Once you have it that far its basically cnc controlled, could put a control on like I did my 88 ton press brake and actual servo valves that have better control yet and viola a cnc brake. If the PLC or cnc control can monitor 2 encoders at once and control 2 valves at once than a double cylinder brake is easily doable as well.

If you get an actual cnc control like the one I did (Icon press brake controller) then you have added benefit of being able to tell it what punch and die you have in, what thickness metal and what angle you want and it calculates the bottom position for you.

I found this online...will keep looking.
http://www.machineaccessoriescorp.com/PDF/CatalogHPCS.pdf

Basic hydraulic circuit


Might be better asking this in the Baileigh forum on here They may have a retrofit system you can buy from them.

JP Machining said:

The hyd schematic would look the same as any other valve running a double acting cylinder (assuming single cylinder variant), except that the valve would need to be an electrically operated proportional valve that the PLC controls. Will need some kind of amplifier between plc and valve too. If going that far than put a linear encoder on the ram and have the PLC watch that too and be able to set the lower limit and upper return point via touchscreen or some other means directly tot he PLC, that way it can be more precise and actually slow the cylinder speed down when getting near the desired position. Once you have it that far its basically cnc controlled, could put a control on like I did my 88 ton press brake and actual servo valves that have better control yet and viola a cnc brake. If the PLC or cnc control can monitor 2 encoders at once and control 2 valves at once than a double cylinder brake is easily doable as well.

If you get an actual cnc control like the one I did (Icon press brake controller) then you have added benefit of being able to tell it what punch and die you have in, what thickness metal and what angle you want and it calculates the bottom position for you.

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Wow it's easy for the scope to go from log splitter valve to full cnc brake when you put it like that lol. What did the control cost you if you don't mind? 4 axis? The servo valves I've seen on eBay and whatnot are not cheap, maybe I'm looking at the wrong ones.

servo valves I got rebuilt ones from ncservo, not cheap but they do like all the work. Id have to look up exact specs and what I paid, cant remember. I got a 6 axis control to run 2 cylinders and currently 2 axis back gage but have plans in the near future of putting movable fingers on back gage adding 2 more axis. IIRC the control alone for 4 axis was about $6k. Dont hold me to that though. best to call up the guys and ask, they were very helpful and patient while I worked out some bugs etc in my system. Best is to get control, valves, and servos, drives all from the same place to be sure everything communicates well together, I didnt and had a few issues. Place I got my control from is : http://www.controlretrofit.com/

The other side to all this, if you are going to go this route of full cnc control, why build it from scratch? Do what I did and find an older press in good condition with a bad controller, gut it out and rewire using the good old iron. My 8' by 88 ton press was about $4k to my door with a control that had hydraulic oil get into the cabinet and kill its old plc. Ripped out all the old wiring that was starting to crack and new servo valves in place of the mechanical contraption it had, some linear encoders from dropros and new hydraulic hardlines to the new valves was basically all I did. (takes time, but you can spread the costs out over time as well).

Even if you dont want full cnc control and old brake may still be able to be updated and run with a basic system for cheaper than building one from scratch. There was a thread somewhere a guy that built one from scratch, but had mach4 or something similar running it. It works, doesnt have all the nice things that a full cnc has or nice graphics to show how to put the part in the press etc, but it worked.

Do to frame flex hydrulic cylinder position is only telling part of the story.

Me i do like the option of a hand pump at times, yeah its slow, yeah its work, but when you have feel your doing wha it takes a whole bunch of sensors to achieve digitally.

I did a bit of a build thread on mine in my shop thread.
http://www.practicalmachinist.com/vb/member-and-shop-photos/jps-shop-298190/index7.html
I think the brake stuff starts around post #254

If you cant see pics, try adding "photobucket hotlink fix" extension to your browser seemed to bring alot of old threads back to life for me.

Why invent the wheel again.
Automec Backgauging Systems for Retrofitting Pressbrakes & Shears

Scruffy887 said:

Why invent the wheel again.
Automec Backgauging Systems for Retrofitting Pressbrakes & Shears

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Have you used one their systems?